CONTAINER SUBSTRATE COMPRESSION PROCESS AND PRODUCT

1 . A compressed horticultural slab comprising:

a substrate including a plurality of fibers compressed in a volume ratio of initial to compressed fiber of 1:4 to 1:20, the plurality of fibers having a shape of the slab, a first set of dimensions when the substrate has a moisture content of up to about 20 to 25 wt. % and a second set of dimensions when the moisture content increases above about 20 to 25 wt. %, based on the total weight of the substrate, the second set of dimensions having greater values than the first set of dimensions.

2 . The slab of claim 1 , wherein the substrate includes wood fiber.

3 . The slab of claim 1 , further comprising fertilizer(s), macronutrient(s), micronutrient(s), mineral(s), binder(s), natural gum(s), surfactant(s), compost, paper, sawdust, or a combination thereof.

4 . The slab of claim 1 , wherein the slab is sterile.

5 . The slab of claim 1 , wherein the slab has higher volume of capillary pores than non-capillary pores.

6 . The slab of claim 1 , wherein the slab's surface is substantially free of bulging when the slab has the first set of dimensions or the second set of dimensions.

7 . The slab of claim 1 , wherein the slab is flexible and breakage-resistant.

8 . The slab of claim 1 , wherein the second set of dimensions is about 1.25 to 5% greater than the first set of dimensions.

9 . A compressed horticultural slab comprising:

a fibrous substrate comprising a plurality of compressed fibers, the substrate having a moisture content of up to about 20 to 25 wt. % and having a final loose bulk density defined by a formula (I):

ρx=ρ 1* x,   (I)

where:

ρx is the final loose bulk density,

ρ 1 is the initial loose bulk density, and

x is the compression factor including any number between 4 and 20,

wherein the compressed slab has a substantially rectangular shape and uniform dimensions throughout its length and a higher volume of capillary pores than non-capillary pores.

10 . The slab of claim 9 , wherein ρ 1 =1.35 lbs/ft 3 .

11 . The slab of claim 9 , wherein x is 12 to 28.

12 . The slab of claim 9 , wherein the slab's surface is substantially free of bulging.

13 . The slab of claim 9 , wherein the substrate includes wood fiber.

14 . A method of forming a compressed horticultural slab, the method comprising:

filling a container with a fiber substrate having a plurality of loose metered fibers having initial loose bulk density ρ 1 ;

pressing the fibers in the container for a dwell time under such pressure that a compression ratio of the initial to compressed fiber of 1:4 to 1:20 and final loose bulk density ρx is achieved, wherein ρx>ρ 1 , while the fibers obtain the shape and at least some dimensions of the container such that the slab is formed; and

removing the slab from the container without compromising the shape and dimensions of the slab.

15 . The method of claim 14 , wherein the pressing is provided in more than one stage.

16 . The method of claim 14 , wherein the dwell time has the same value in each stage.

17 . The method of claim 14 , wherein the pressing is provided in a temperature range of 60 to 350 F (15.5 to 177° C.).

18 . The method of claim 14 , wherein the container has a predetermined fill line and the filling includes filling the container with the fibers evenly below the fill line and unevenly above the fill line.

19 . The method of claim 14 , wherein the filling includes applying a lesser amount of fibers to a container's central portion than the amount of fibers provided around a perimeter of the container.

20 . The method of claim 14 , wherein the pressing includes decreasing a volume of non-capillary pores in the fiber substrate by compressing the substrate to the desired final loose bulk density ρx.